U.S. patent application number 17/601724 was filed with the patent office on 2022-06-02 for method for the manufacture of electrodes.
The applicant listed for this patent is Politecnico di Torino, SOLVAY SA. Invention is credited to Julio A. ABUSLEME, Daniele BATTEGAZZORE, Maurizio BISO, Alberto FRACHE, Francesco LIBERALE.
Application Number | 20220173379 17/601724 |
Document ID | / |
Family ID | |
Filed Date | 2022-06-02 |
United States Patent
Application |
20220173379 |
Kind Code |
A1 |
ABUSLEME; Julio A. ; et
al. |
June 2, 2022 |
METHOD FOR THE MANUFACTURE OF ELECTRODES
Abstract
The present invention pertains to an electrode-forming
composition, to use of said electrode-forming composition in a
process for the manufacture of an electrode, to said electrode and
to an electrochemical device comprising said electrode.
Inventors: |
ABUSLEME; Julio A.;
(Saronno, IT) ; BISO; Maurizio; (Milano, IT)
; FRACHE; Alberto; (Alessandria, IT) ;
BATTEGAZZORE; Daniele; (Alessandria, IT) ; LIBERALE;
Francesco; (Pavia, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SOLVAY SA
Politecnico di Torino |
Brussels
Torino |
|
BE
IT |
|
|
Appl. No.: |
17/601724 |
Filed: |
April 29, 2020 |
PCT Filed: |
April 29, 2020 |
PCT NO: |
PCT/EP2020/061825 |
371 Date: |
October 6, 2021 |
International
Class: |
H01M 4/1393 20060101
H01M004/1393; H01M 10/0525 20060101 H01M010/0525; H01M 4/62
20060101 H01M004/62 |
Foreign Application Data
Date |
Code |
Application Number |
May 3, 2019 |
EP |
19172469.9 |
Feb 3, 2020 |
EP |
20155055.5 |
Claims
1-15. (canceled)
16. A composition [composition (C)] comprising: from 0.5 wt. % to
less than 20 wt. % of at least one semi-crystalline partially
fluorinated polymer [polymer (F)] comprising recurring units
derived from 1,1-difluoroethylene (VDF); from 10 wt. % to less than
60 wt. % of at least one liquid medium [medium (L)] characterized
by a boiling point equal to or higher than 150.degree. C.; and at
least 50 wt. % of at least one electro-active compound [compound
(EA)]; wherein the above amounts are based on the total weight of
said composition (C), wherein said polymer (F) is characterized by
an intrinsic viscosity higher than 0.05 L/g, the intrinsic
viscosity being measured from the dropping time of a solution of
said polymer (F1) at 25.degree. C. at a concentration of 0.2 g/dL
in N.N-dimethylformamide using a Ubbelhode viscosimeter.
17. The composition (C) according to claim 16, wherein said polymer
(F) comprising recurring units derived from 1,1-difluoroethylene
(VDF) and recurring units derived from at least one hydrogenated
monomer comprising at least one carboxylic acid end group [monomer
(MA)] and/or recurring units derived from at least one partially or
fully fluorinated monomer [monomer (F.sub.FH)], said monomer
(F.sub.FH) being different from VDF.
18. The composition (C) according to claim 17, wherein: said
monomer (MA) complies with the following chemical formula (II):
##STR00006## wherein: R'.sub.1, R'.sub.2 and R'.sub.3 are hydrogen
atoms, and R'.sub.OH s a hydrogen atom or a C.sub.1-C.sub.5
hydrocarbon moiety comprising at least one hydroxyl group; and said
monomer (F.sub.FH) is selected in the group comprising:
C.sub.2-C.sub.8 perfluoroolefins; C.sub.2-C.sub.8 hydrogenated
fluoroolefins different from VDF; CH.sub.2.dbd.CH--R.sub.f0 wherein
R.sub.f0 is a C.sub.1-C.sub.6 perfluoroalkyl; chloro- and/or bromo-
and/or iodo-C.sub.2-C.sub.6 fluoroolefins; CF.sub.2.dbd.CFOX.sub.0
wherein X.sub.0 is a C.sub.1-C.sub.6 fluoro- or perfluoroalkyl; a
C.sub.1-C.sub.12 alkyl group, a C.sub.1-C.sub.12 oxyalkyl group or
a C.sub.1-C.sub.12 (per)fluorooxyalkyl group having one or more
ether groups; group --CF.sub.2OR.sub.f2 wherein R.sub.f2 is a
C.sub.1-C.sub.6 fluoro- or perfluoroalkyl group or a
C.sub.1-C.sub.6 (per)fluorooxyalkyl group having one or more ether
groups; CF.sub.2.dbd.CFOY.sub.0 wherein Y.sub.0 is a
C.sub.1-C.sub.12 alkyl group or (per)fluoroalkyl group, a
C.sub.1-C.sub.12 oxyalkyl group or a C.sub.1-C.sub.12
(per)fluorooxyalkyl group having one or more ether groups and Yo
comprising a carboxylic or sulfonic acid group, in its acid, acid
halide or salt form; fluorodioxoles.
19. The composition (C) according to claim 16, wherein said polymer
(F) comprises: recurring units derived from VDF and recurring units
derived from at least one monomer (MA) [polymer (F*)]; or recurring
units derived from VDF, recurring units derived from at least one
monomer (MA) and recurring units derived from at least one monomer
(F.sub.FH) [polymer (F**)]; or recurring units derived from VDF,
and recurring units derived from at least one monomer (F.sub.FH)
[polymer (F{circumflex over ( )})].
20. The composition (C) according to claim 19, wherein: said
polymer (F*) comprises: at least 90% by moles of recurring units
derived from VDF, from 0.05% to 10% by moles of recurring units
derived from at least one monomer (MA); said polymer (F**)
comprises: at least 80% by moles of recurring units derived from
VDF, from 0.01% to 10% by moles of recurring units derived from at
least one monomer (MA), and from 0.1% to 15% by moles of at least
one monomer (F.sub.FH); and said polymer (F{circumflex over ( )})
comprises: at least 80% by moles of recurring units derived from
VDF, and from 0.1% to 15% by moles of at least one monomer
(F.sub.FH).
21. The composition (C) according to claim 16, wherein said
composition (C) comprises a conductive compound [compound (C)].
22. The composition (C) according to claim 21, wherein said
compound (C) is present in said composition (C) in an amount from
0.1 wt. % to 15 wt. % based on the total weight of said composition
(C).
23. The composition (C) according to claim 16, wherein said
composition (C) comprises a polymer [polymer (P)] comprising a
backbone complying with the following formula:
--[(CH.sub.2).sub.x--CHR.sup.1--R.sup.2)-- wherein x is in integer
from 1 to 3, R.sup.1 is hydrogen or methyl group; and R.sup.2 is
oxygen atom or a group of formula --OC(.dbd.O)R.sup.3 with R.sup.3
being hydrogen atom or methyl, said polymer (P) has a melting point
(Tm) higher than 25.degree. C. and lower than 120.degree. C.
24. The composition (C) according to claim 23, wherein said polymer
(P) is present in said composition (C) in an amount higher than 0.1
wt. % and lower than 20 wt. %, based on the total weight of said
composition (C).
25. The composition (C) according to claim 16, said composition (C)
comprising: from 18 to 40.5 w. % of said medium (L), optionally
comprising at least one salt (M); from 2 to 14 w. % of said polymer
(F); from 52 to 82 wt. % of said compound (EA); from 0.5 to 10 wt.
% of said compound (C); and optionally, from 3 to 5 wt. % of said
polymer (P).
26. The composition (C) according to claim 16, said composition (C)
comprising being composition (C) of the invention is composition
(C-1), which comprises: from 10 to 40 wt. % of said medium (L),
said medium (L) comprising at least one organic carbonate as the
only medium (L); from 2 to 14 w. % of polymer (F**-1), wherein
polymer (F**-1) comprises: at least 80% by moles of recurring units
derived from VDF, from 0.01% to 10% by moles of recurring units
derived from at least one monomer (MA), and from 5% to 12% by moles
of at least one monomer (FFH); from 52 to 82 wt. % of said compound
(EA); from 0.5 to 10 wt. % of said compound (C); and optionally,
from 3 to 5 wt. % of said polymer (P).
27. A process for the manufacture of an assembly, said process
comprising: (i) providing a substrate; (ii) providing the
composition (C) of claim 16; (iii) heating said composition (C) at
a temperature higher than 100.degree. C.; (iv) extruding the
composition (C) provided in step (ii) onto the substrate provided
in step (i), thereby providing an assembly comprising a substrate
coated with at least one layer consisting of said composition
(C).
28. A process for the manufacture of an assembly, said process
comprising: (a) providing a substrate; (b) providing the
composition (C-1) of claim 26 in the form of pellets; (c) heating
said composition (C-1) at a temperature higher than 100.degree. C.;
(d) extruding the composition (C-1) provided in step (b) onto the
substrate provided in step (a), thereby providing an assembly
comprising a substrate coated with at least one layer consisting of
said composition (C-1).
29. An assembly comprising: at least one substrate, and directly
adhered onto said substrate, at least one layer [layer (L1)]
consisting of the composition (C) of claim 16, wherein said
assembly is a positive electrode or a negative electrode.
30. A secondary battery comprising: a positive electrode, a
negative electrode, and a membrane interposed between said positive
electrode and said negative electrode, wherein at least one of said
positive electrode and said negative electrode is the assembly
according to claim 29.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to European application No.
19172469.9 filed on May 3, 2019 and to European application No.
20155055.5 filed on Feb. 3, 2020, the whole content of those
applications being incorporated herein by reference for all
purposes.
TECHNICAL FIELD
[0002] The present invention pertains to an electrode-forming
composition, to use of said electrode-forming composition in a
process for the manufacture of an electrode, to said electrode and
to an electrochemical device comprising said electrode.
BACKGROUND ART
[0003] To date, techniques for manufacturing either positive or
negative electrodes involve the use of organic solvents such as
N-methyl-2-pyrrolidone (also referred to as "NMP") for dissolving
fluoropolymer binders and homogenizing them with an electro-active
material and all other suitable components to produce a paste to be
applied to a metal collector.
[0004] The role of the organic solvent is typically to dissolve the
fluoropolymer in order to bind the electro-active material
particles to each together and to the metal collector upon
evaporation of the organic solvent. The polymer binder should
properly bind the electro-active material particles together and to
the metal collector so that these particles can chemically
withstand large volume expansion and contraction during charging
and discharging cycles.
[0005] Although NMP is a solvent widely used for dissolving
fluoropolymers, because of its costs and environmental concerns,
this solvent is recycled. However, the use of NMP is raising issues
from both human health and environmental impact perspective.
[0006] Therefore, recently the need was felt for alternative
processes for the manufacture of electrodes in the absence of
solvents.
[0007] For example, WO 2018/050314 (in the name of Robert Bosch
GmbH) discloses a method for producing an electrode film, wherein a
particle mixture is produced from particles of a polymer binder and
conductive carbon black by premixing, then agglomerates are
produced by compacting said particles and, after addition of an
electrochemical active material, the electrode film is manufactured
by rolling or extrusion. Thus, this patent application described a
process wherein solid particles are mixed, then compacted into
agglomerates, which are then reduced in size and sieved, before
rolling or extruding said solid mixture. While in the description a
solvent is said that may be added, there is no example (nor
reference in the accompanying figures) of a process wherein the
mixture to be processed is liquid. Indeed, the entire description
and the figures referred to a process wherein a solid mixture is
used.
SUMMARY OF INVENTION
[0008] The Applicant perceived that the need still exists for a
process for the manufacture of electrodes, wherein no solvent (like
NMP) is used to dissolve the fluoropolymer and hence no recycle is
needed.
[0009] The Applicant surprisingly found that the above technical
problem can be solved by using the composition in the process
according to the present invention.
[0010] Indeed, the Applicant surprisingly found that by melt
extruding the composition of the invention, it is possible to
manufacture electrodes suitable for use in electrochemical
devices.
[0011] Thus, in a first aspect, the present invention relates to a
composition [composition (C)] comprising: [0012] from 0.5 wt. % to
less than 20 wt. %, preferably to less than 15 wt. % of at least
one semi-crystalline partially fluorinated polymer [polymer (F)]
comprising recurring units derived from 1,1-difluoroethylene (VDF);
[0013] from 10 wt. % to less than 60 wt. %, preferably to less than
41 wt. %, of at least one liquid medium [medium (L)] characterized
by a boiling point equal to or higher than 150.degree. C.; and
[0014] at least 50 wt. % of at least one electro-active compound
[compound (EA)];
[0015] wherein the above amounts are based on the total weight of
said composition (C).
[0016] In a second aspect, the present invention pertains to the
use of said composition (C) in a process for the manufacture of an
assembly, more preferably an electrode [electrode (E)].
[0017] In a third aspect, the present invention relates to a
process for the manufacture of an assembly, said process
comprising:
[0018] (i) providing a substrate;
[0019] (ii) providing composition (C) as defined above;
[0020] (iii) heating said composition (C) at a temperature higher
than 100.degree. C.;
[0021] (iv) extruding the composition (C) provided in step (ii)
onto the substrate provided in step (i), thereby providing an
assembly comprising a substrate coated with at least one layer
consisting of said composition (C).
[0022] In a fourth aspect, the present invention relates to an
assembly obtained with the above-mentioned process.
[0023] Advantageously, said assembly comprises: [0024] at least one
substrate, and [0025] directly adhered onto said substrate, at
least one layer [layer (L1)] consisting of a composition
[composition (C2)] comprising: [0026] at least one polymer (F) as
defined above, [0027] at least one compound (EA) as defined above,
[0028] at least one liquid medium [medium (L)] as defined
above.
[0029] Advantageously, said assembly is an electrode [electrode
(E)]. More preferably, said electrode (E) is a cathode or an
anode.
[0030] The electrode (E) of the invention is particularly suitable
for use in electrochemical devices.
[0031] Non-limiting examples of suitable electrochemical devices
include secondary batteries, preferably an alkaline or an
alkaline-earth secondary battery. More preferably, said secondary
battery is a lithium-ion secondary battery.
DESCRIPTION OF EMBODIMENTS
[0032] As used within the present description and in the following
claims: [0033] the use of parentheses around symbols or numbers
identifying the formulae, for example in expressions like "polymer
(P)", etc., has the mere purpose of better distinguishing the
symbol or number from the rest of the text and, hence, said
parenthesis can also be omitted; [0034] the terms
"1,1-difluoroethylene", "1,1-difluoroethene" and "vinylidene
fluoride" are used as synonyms; [0035] the terms
"poly-(1,1-difluoroethylene)" and "polyvinylidene fluoride" are
used as synonyms; [0036] the term "secondary battery" is intended
to denote a rechargeable battery; [0037] the term "electro-active
compound [compound (EA)]" is intended to denote a compound which is
able to incorporate or insert into its structure and substantially
release therefrom alkaline or alkaline-earth metal ions during the
charging phase and the discharging phase of an electrochemical
device. The compound (EA) is preferably able to incorporate or
insert and release lithium ions; [0038] the expression "partially
fluorinated polymer" is intended to denote a polymer comprising
recurring units derived from at least one fluorinated monomer and,
optionally, at least one hydrogenated monomer, wherein at least one
of said fluorinated monomer and said hydrogenated monomer comprises
at least one hydrogen atom; [0039] the term "fluorinated monomer"
is intended to denote an ethylenically unsaturated monomer
comprising at least one fluorine atom; [0040] the term
"hydrogenated monomer" is intended to denote an ethylenically
unsaturated monomer comprising at least one hydrogen atom and free
from fluorine atoms; [0041] the expression "at least one
fluorinated monomer" is intended to indicate that the polymer may
comprise recurring units derived from one or more than one
fluorinated monomers; [0042] the expression "fluorinated monomers"
is intended both in the plural and the singular, that is to say
that they denote both one or more than one fluorinated monomers as
defined above; [0043] the expression "at least one hydrogenated
monomer" is intended to indicate recurring units derived from one
or more than one hydrogenated monomers; [0044] the expression
"hydrogenated monomers" is intended both in the plural and the
singular, that is to say that they denote both one or more than one
hydrogenated monomers as defined above.
[0045] The term "semi-crystalline" is hereby intended to denote a
polymer (F) having a heat of fusion of from 5 to 90 J/g, preferably
of from 30 to 60 J/g, as measured according to ASTM D3418-08.
[0046] Advantageously, said polymer (F) is characterized by an
intrinsic viscosity higher than 0.05 L/g, more preferably higher
than 0.12 L/g and even more preferably higher than 0.25 L/g, the
intrinsic viscosity being measured as the dropping time of a
solution of said polymer (F1) at 25.degree. C. at a concentration
of 0.2 g/dL in N.N-dimethylformamide using a Ubbelhode
viscosimeter, as detailed in the Experimental Section.
[0047] Preferably, said polymer (F) comprising recurring units
derived from 1,1-difluoroethylene (VDF) and recurring units derived
from at least one hydrogenated monomer comprising at least one
carboxylic acid end group [monomer (MA)] and/or recurring units
derived from at least one partially or fully fluorinated monomer
[monomer (F.sub.FH)], said monomer (F.sub.FH) being different from
VDF.
[0048] According to a preferred embodiment, said polymer (F)
comprises, more preferably consists of:
[0049] (I) recurring units derived from VDF and
[0050] (II) recurring units derived from at least one monomer
(MA).
[0051] Polymer (F) according to this embodiment will be herein
after referred to as "polymer (F*)".
[0052] Preferably, said polymer (F*) comprises, more preferably
consists of: [0053] at least 90% by moles, preferably at least 95%
by moles, more preferably at least 97% by moles of recurring units
derived from VDF, [0054] from 0.05% to 10% by moles, preferably
from 0.1% to 5% by moles, more preferably from 0.2% to 3% by moles
of recurring units derived from at least one monomer (MA).
[0055] According to a preferred embodiment, said polymer (F)
comprises, more preferably consists of:
[0056] (I) recurring units derived from VDF,
[0057] (II) recurring units derived from at least one monomer (MA)
and
[0058] (III) recurring units derived from at least one monomer
(F.sub.FH).
[0059] Polymer (F) according to this embodiment will be herein
after referred to as "polymer (F**)".
[0060] Preferably, said polymer (F**) comprises, more preferably
consists of: [0061] at least 80% by moles, preferably at least 85%
by moles, more preferably at least 90% by moles of recurring units
derived from VDF, [0062] from 0.01% to 10% by moles, preferably
from 0.05% to 5% by moles, more preferably from 0.1% to 1.5% by
moles of recurring units derived from at least one monomer (MA),
and [0063] from 0.1% to 15% by moles, preferably from 0.5% to 12%
by moles, more preferably from 1% to 10% by moles of at least one
monomer (F.sub.FH).
[0064] In a particularly preferred embodiment of the present
invention, said polymer (F**) is polymer (F**-1), which comprises,
more preferably consists of: [0065] at least 80% by moles,
preferably at least 85% by moles, more preferably at least 90% by
moles of recurring units derived from VDF, [0066] from 0.01% to 10%
by moles, preferably from 0.05% to 5% by moles, more preferably
from 0.1% to 1.5% by moles of recurring units derived from at least
one monomer (MA), and [0067] from 5% to 12% by moles, more
preferably from 6% to 10% by moles of at least one monomer
(FFH).
[0068] The polymer (F**) may be obtained by polymerization of a VDF
monomer, at least one monomer (MA) and at least one monomer (FFH)
according to the teaching, for example, of WO 2008/129041.
[0069] Advantageously, said polymer (F*) and said polymer (F**) are
characterized by an intrinsic viscosity higher than 0.25 L/g and
lower than 0.60 L/g, the intrinsic viscosity being measured as the
dropping time of a solution of said polymer (F*) or (F**) at
25.degree. C. at a concentration of 0.2 g/dL in
N.N-dimethylformamide using a Ubbelhode viscosimeter, as detailed
in the Experimental Section.
[0070] According to a preferred embodiment, said polymer (F)
comprises, preferably consists of:
[0071] (I) recurring units derived from VDF, and
[0072] (II) recurring units derived from at least one monomer
(F.sub.FH).
[0073] Polymer (F) according to this embodiment will be herein
after referred to as "polymer (F{circumflex over ( )})".
[0074] More preferably, said polymer (F{circumflex over ( )})
comprises: [0075] at least 80% by moles, preferably at least 85% by
moles, more preferably at least 90% by moles of recurring units
derived from VDF, and [0076] from 0.1% to 15% by moles, preferably
from 0.5% to 12% by moles, more preferably from 1% to 10% by moles
of at least one monomer (F.sub.FH).
[0077] Advantageously, said polymer (F{circumflex over ( )}) is
characterized by an intrinsic viscosity higher than 0.05 L/g and
lower than 0.60 L/g, more preferably lower than 0.25 L/g, the
intrinsic viscosity being measured as the dropping time of a
solution of said polymer (F{circumflex over ( )}) at 25.degree. C.
at a concentration of 0.2 g/dL in N.N-dimethylformamide using a
Ubbelhode viscosimeter, as detailed in the Experimental
Section.
[0078] Determination of average mole percentage of recurring units
derived from at least one monomer (MA) in the polymer (F) can be
performed by any suitable method. Mention can be notably made of
acid-base titration methods, well suited e.g. for the determination
of the acrylic acid content, of NMR methods, adequate for the
quantification of monomers (MA) comprising aliphatic hydrogen atoms
in side chains, of weight balance based on total fed monomer (MA)
and unreacted residual monomer (MA) during polymer (F)
manufacture.
[0079] Advantageously, said monomer (MA) complies with the
following chemical formula:
##STR00001##
[0080] wherein: [0081] R'.sub.1, R'.sub.2 and R'.sub.3 are hydrogen
atoms, and [0082] R'.sub.OH is a hydrogen atom or a C.sub.1-C.sub.5
hydrocarbon moiety comprising at least one hydroxyl group.
[0083] Non-limiting examples of said monomer (MA) are, notably,
acrylic acid, methacrylic acid, hydroxyethylmethacrylate,
hydroxyethylacrylate, hydroxypropylmethacrylate,
hydroxypropylacrylate, hydroxyethylhexyl methacrylate,
hydroxyethylhexylacrylate, and mixtures thereof.
[0084] Preferably, said monomer (MA) is selected from the group
comprising, more preferably consisting of: [0085] hydroxyethyl
acrylate (HEA) of formula:
[0085] ##STR00002## [0086] 2-hydroxypropyl acrylate (HPA) of either
of formulae:
[0086] ##STR00003## [0087] acrylic acid (AA) of formula:
[0087] ##STR00004## [0088] and mixtures thereof.
[0089] According to a preferred embodiment, said monomer (MA) is
acrylic acid (AA).
[0090] Preferably, said monomer (F.sub.FH) is selected in the group
comprising, more preferably consisting of: [0091] C.sub.2-C.sub.8
perfluoroolefins, such as tetrafluoroethylene (TFE) and
hexafluoropropylene (HFP); [0092] C.sub.2-C.sub.8 hydrogenated
fluoroolefins different from VDF, such as vinyl fluoride,
1,2-difluoroethylene and trifluoroethylene; [0093]
CH.sub.2.dbd.CH--R.sub.f0 wherein R.sub.f0 is a C.sub.1-C.sub.6
perfluoroalkyl; [0094] chloro- and/or bromo- and/or
iodo-C.sub.2-C.sub.6 fluoroolefins, such as chlorotrifluoroethylene
(CTFE); [0095] CF.sub.2.dbd.CFOX.sub.0 wherein X.sub.0 is a
C.sub.1-C.sub.6 fluoro- or perfluoroalkyl, e.g. CF.sub.3,
C.sub.2F.sub.5, C.sub.3F.sub.7; a C.sub.1-C.sub.12 alkyl group, a
C.sub.1-C.sub.12 oxyalkyl group or a C.sub.1-C.sub.12
(per)fluorooxyalkyl group having one or more ether groups, such as
perfluoro-2-propoxy-propyl group; group --CF.sub.2OR.sub.f2 wherein
R.sub.f2 is a C.sub.1-C.sub.6 fluoro- or perfluoroalkyl group, e.g.
CF.sub.3, C.sub.2F.sub.5, C.sub.3F.sub.7 or a C.sub.1-C.sub.6
(per)fluorooxyalkyl group having one or more ether groups such as
--C.sub.2F.sub.5--O--CF.sub.3; [0096] CF.sub.2.dbd.CFOY.sub.0
wherein Y.sub.0 is a C.sub.1-C.sub.12 alkyl group or
(per)fluoroalkyl group, a C.sub.1-C.sub.12 oxyalkyl group or a
C.sub.1-C.sub.12 (per)fluorooxyalkyl group having one or more ether
groups and Y.sub.0 comprising a carboxylic or sulfonic acid group,
in its acid, acid halide or salt form; [0097] fluorodioxoles,
preferably perfluorodioxoles.
[0098] More preferably, said monomer (F.sub.FH) is selected in the
group comprising, preferably consisting of: vinyl fluoride
(VF.sub.1), chlorotrifluoroethylene (CTFE), hexafluoropropylene
(HFP), tetrafluoroethylene (TFE), trifluoroethylene (TrFE) and
perfluoromethylvinylether (PMVE).
[0099] Polymer (F) is typically obtainable by emulsion
polymerization or suspension polymerization according to the
methods known to the skilled person in this field.
[0100] The nature of the compound (EA) in composition (C) and as a
consequence in layer (L1) of the assembly of the invention, depends
on whether the final assembly thereby provided is a positive
electrode [electrode (Ep)] or a negative electrode [electrode
(En)].
[0101] In the case of forming a positive electrode for a
lithium-ion secondary battery, said compound (EA) may comprise a
composite metal chalcogenide of formula LiMQ.sub.2, wherein M is at
least one metal selected from transition metals such as Co, Ni, Fe,
Mn, Cr and V and Q is a chalcogen such as O or S. Among these, it
is preferred to use a lithium-based composite metal oxide of
formula LiMO.sub.2, wherein M is the same as defined above.
Preferred examples thereof may include LiCoO.sub.2, LiNiO.sub.2,
LiNi.sub.xCo.sub.1-xO.sub.2 (0<x<1) and spinel-structured
LiMn.sub.2O.sub.4.
[0102] As an alternative, still in the case of forming a positive
electrode for a lithium-ion secondary battery, the compound (EA)
may comprise a lithiated or partially lithiated transition metal
oxyanion-based electro-active material of formula
M.sub.1M.sub.2(JO.sub.4).sub.fE.sub.1-f, wherein M.sub.1 is
lithium, which may be partially substituted by another alkali metal
representing less that 20% of the M.sub.1 metals, M.sub.2 is a
transition metal at the oxidation level of +2 selected from Fe, Mn,
Ni or mixtures thereof, which may be partially substituted by one
or more additional metals at oxidation levels between +1 and +5 and
representing less than 35% of the M.sub.2 metals, including 0,
JO.sub.4 is any oxyanion wherein J is either P, S, V, Si, Nb, Mo or
a combination thereof, E is a fluoride, hydroxide or chloride
anion, f is the molar fraction of the JO.sub.4 oxyanion, generally
comprised between 0.75 and 1.
[0103] The M.sub.1M.sub.2(JO.sub.4).sub.fE.sub.1-f electro-active
material as defined above is preferably phosphate-based and may
have an ordered or modified olivine structure.
[0104] More preferably, the compound (EA) has formula
Li.sub.3-xM'.sub.yM''.sub.2-y(JO.sub.4).sub.3 wherein
0.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.2, M' and M'' are the same
or different metals, at least one of which being a transition
metal, JO.sub.4 is preferably PO.sub.4 which may be partially
substituted with another oxyanion, wherein J is either S, V, Si,
Nb, Mo or a combination thereof. Still more preferably, the
compound (EA) is a phosphate-based electro-active material of
formula Li(Fe.sub.xMn.sub.1-x)PO.sub.4 wherein 0.ltoreq.x.ltoreq.1,
wherein x is preferably 1 (that is to say, lithium iron phosphate
of formula LiFePO.sub.4).
[0105] Preferably, said compound (EA) is selected from
lithium-containing complex metal oxides of general formula (I)
LiNi.sub.xM.sup.1.sub.yM.sup.2.sub.zY.sub.2 (I)
[0106] wherein M.sup.1 and M.sup.2 are the same or different from
each other and are transition metals selected from Co, Fe, Mn, Cr
and V,
[0107] 0.5.ltoreq.x.ltoreq.1,
[0108] wherein y+z =1-x, and
[0109] Y denotes a chalcogen, preferably selected from O and S.
[0110] The positive electrode active material (AM) is preferably a
compound of formula (I) wherein Y is O.
[0111] In a preferred embodiment, M.sup.1 is Mn and M.sup.2 is
Co.
[0112] In another preferred embodiment, M.sup.1 is Co and M.sup.2
is Al.
[0113] Examples of such active materials include
LiNi.sub.xMn.sub.yCo.sub.zO.sub.2, herein after referred to as NMC,
and LiNi.sub.xCo.sub.yAl.sub.zO.sub.2, herein after referred to as
NCA.
[0114] Specifically with respect to
LiNi.sub.xMn.sub.yCo.sub.zO.sub.2, varying the content ratio of
manganese, nickel, and cobalt can tune the power and energy
performance of a battery.
[0115] In a preferred embodiment of the present invention, the
active material
[0116] (AM) is a compound of formula (I) as above defined, wherein
0.5.ltoreq.x.ltoreq.1, 0.1.ltoreq.y.ltoreq.0.5, and
0.ltoreq.z.ltoreq.0.5.
[0117] Non limitative examples of suitable positive electrode
active materials (AM) of formula (I) include, notably:
[0118] LiNi.sub.0.5Mn.sub.0.3Co.sub.0.2O.sub.2,
[0119] LiNi.sub.0.6Mn.sub.0.2Co.sub.0.2O.sub.2,
[0120] LiNi.sub.0.8Mn.sub.0.1Co.sub.0.1O.sub.2,
[0121] LiNi.sub.0.8Co.sub.0.15Al.sub.0.05O.sub.2, and
[0122] LiNi.sub.0.8Co.sub.0.2O.
[0123] Active materials (AM) which have been found particularly
advantageous are LiNi.sub.0.8Co.sub.0.15Al.sub.0.05O.sub.2,
LiNi.sub.0.6Mn.sub.0.2Co.sub.0.2O.sub.2and
LiNi.sub.0.8Mn.sub.0.1Co.sub.0.1O.sub.2.
[0124] In the case of forming a negative electrode (En) for a
Lithium-ion secondary battery, the compound (EA) may preferably
comprise a carbon-based material and/or a silicon-based
material.
[0125] In some embodiments, the carbon-based material may be, for
example, graphite, such as natural or artificial graphite,
graphene, or carbon black.
[0126] These materials may be used alone or as a mixture of two or
more thereof.
[0127] The carbon-based material is preferably graphite.
[0128] The silicon-based compound may be one or more selected from
the group consisting of chlorosilane, alkoxysilane, aminosilane,
fluoroalkylsilane, silicon, silicon chloride, silicon carbide and
silicon oxide. More particularly, the silicon-based compound may be
silicon oxide or silicon carbide.
[0129] When present in compound (EA), the at least one
silicon-based compound is comprised in the compound (EA) in an
amount ranging from 1 to 50% by weight, preferably from 5 to 20% by
weight with respect to the total weight of the compound (EA).
[0130] For the purpose of the present invention, the term "liquid
medium [medium (L)]" is intended to denote a medium comprising one
or more substances in the liquid state at 20.degree. C. under
atmospheric pressure.
[0131] The medium (L) is typically free from any solvent [solvent
(S)].
[0132] Within the present invention, solvent (S) is intended to
denote a solvent suitable for dissolving polymer (F) as defined
above. To this aim, solvent (S) is typically selected from polar
solvents, including N-methyl-2-pyrrolidone (NMP),
N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide,
hexamethylphosphamide, dioxane, tetrahydrofuran, tetramethylurea,
triethyl phosphate, trimethyl phosphate; and mixtures thereof.
[0133] Said medium (L) is preferably selected from organic
carbonates, ionic liquids (IL), or mixture thereof.
[0134] According to a first embodiment of the invention, said
medium (L) comprises at least one organic carbonate as the only
medium (L).
[0135] Non-limiting examples of suitable organic carbonates
include, notably, ethylene carbonate, propylene carbonate, mixtures
of ethylene carbonate and propylene carbonate, dimethyl carbonate,
diethyl carbonate, ethyl-methyl carbonate, butylene carbonate,
vinylene carbonate, fluoroethylene carbonate, fluoropropylene
carbonate and mixtures thereof.
[0136] According to a second embodiment of the invention, said
medium (L) comprises at least one ionic liquid (IL) as the only
medium (L).
[0137] By the term "ionic liquid (IL)", it is hereby intended to
denote a compound formed by the combination of positively charged
cations and negatively charged anions which exists in the liquid
state at temperatures below 100.degree. C. under atmospheric
pressure.
[0138] The ionic liquid (IL) can be selected from protic ionic
liquids (IL.sub.p), aprotic ionic liquids (IL.sub.a) and mixtures
thereof.
[0139] By the term "protic ionic liquid (IL.sub.p)", it is hereby
intended to denote an ionic liquid wherein the cation comprises one
or more H+ hydrogen ions.
[0140] Non-limitative examples of cations comprising one or more H+
hydrogen ions include, notably, imidazolium, pyridinium,
pyrrolidinium or piperidinium rings, wherein the nitrogen atom
carrying the positive charge is bound to a H+ hydrogen ion.
[0141] By the term "aprotic ionic liquid (IL.sub.a)", it is hereby
intended to denote an ionic liquid wherein the cation is free of H+
hydrogen ions.
[0142] The ionic liquid (IL) is typically selected from those
comprising as cation a sulfonium ion or an imidazolium, pyridinium,
pyrrolidinium or piperidinium ring, said ring being optionally
substituted on the nitrogen atom, in particular by one or more
alkyl groups with 1 to 8 carbon atoms, and on the carbon atoms, in
particular by one or more alkyl groups with 1 to 30 carbon
atoms.
[0143] According to a third embodiment of the invention, said
medium (L) comprises a mixture of at least one organic carbonate as
defined above and at least one ionic liquid (IL) as defined
above.
[0144] According to a preferred embodiment, said composition (C)
further comprises at least one metal salt [salt (M)].
[0145] Said salt (M) is typically selected from the group
consisting of: (a) MeI, Me(PF.sub.6).sub.n, Me(BF.sub.4).sub.n,
Me(ClO.sub.4).sub.n, Me(bis(oxalato)borate).sub.n
("Me(BOB).sub.n"), MeCF.sub.3SO.sub.3,
Me[N(CF.sub.3SO.sub.2).sub.2].sub.n,
Me[N(C.sub.2F.sub.5SO.sub.2).sub.2].sub.n,
Me[N(CF.sub.3SO.sub.2)(R.sub.FSO.sub.2)].sub.n, wherein R.sub.F is
C.sub.2F.sub.5, C.sub.4F.sub.9 or CF.sub.3OCF.sub.2CF.sub.2,
Me(AsF.sub.6).sub.n, Me[C(CF.sub.3SO.sub.2).sub.3].sub.n,
Me.sub.2Sn,
[0146] wherein Me is a metal, preferably a transition metal, an
alkaline metal or an alkaline-earth metal, more preferably Me being
Li, Na, K or Cs, even more preferably Me being Li, and n is the
valence of said metal, typically n being 1 or 2,
##STR00005##
[0147] wherein R'.sub.F is selected from the group consisting of F,
CF.sub.3, CHF.sub.2, CH.sub.2F, C.sub.2HF.sub.4,
C.sub.2H.sub.2F.sub.3, C.sub.2H.sub.3F.sub.2, C.sub.2F.sub.5,
C.sub.3F.sub.7, C.sub.3H.sub.2F.sub.5, C.sub.3H.sub.4F.sub.3,
C.sub.4F.sub.9, C.sub.4H.sub.2F.sub.7, C.sub.4H.sub.4F.sub.5,
C.sub.5F.sub.11, C.sub.3F.sub.5OCF.sub.3, C.sub.2F.sub.4OCF.sub.3,
C.sub.2H.sub.2F.sub.2OCF.sub.3 and CF.sub.2OCF.sub.3, and (c)
combinations thereof.
[0148] Said salt (M) is advantageously dissolved by said medium
(L).
[0149] On this regard, the concentration of said salt (M) in the
medium (L) is advantageously at least 0.01 M, preferably at least
0.025 M, more preferably at least 0.05 M.
[0150] The concentration of the salt (M) in the medium (L) is
advantageously at most 3 M, preferably at most 2 M, more preferably
at most 1 M.
[0151] Advantageously, said composition (C) further comprises a
conductive compound [compound (C)], which is able to impart
electron conductivity to the electrode.
[0152] Examples thereof may include: carbonaceous materials, such
as carbon black, graphite fine powder carbon nanotubes, graphene,
or fiber, or fine powder or fibers of metals such as nickel or
aluminum.
[0153] Said compound (C) is preferably selected from carbon black
or graphite.
[0154] For sake of clarity, compound (C) is different from the
carbon-based material described above for the negative electrode
(En).
[0155] Preferably, said compound (C) is present in said composition
(C) in an amount from 0.1 wt. % to 15 wt. %, more preferably from
0.25 to 12 wt. % based on the total weight of said composition
(C).
[0156] Advantageously, said composition (C) further comprises at
least one polymer [polymer (P)] comprising a backbone complying
with the following formula:
--[(CH.sub.2).sub.x--CHR.sup.1--R.sup.2)--
[0157] wherein
[0158] x is in integer from 1 to 3,
[0159] R.sup.1 is hydrogen or methyl group; and
[0160] R.sup.2 is oxygen atom or a group of formula
--OC(.dbd.O)R.sup.3 with R.sup.3 being hydrogen atom or methyl.
[0161] Preferably, said polymer (P) has a melting point (Tm) lower
than 120.degree. C., more preferably lower than 100.degree. C.,
even more preferably lower than 90.degree. C.
[0162] Preferably, said polymer (P) has a melting point (Tm) higher
than 25.degree. C., more preferably higher than 30.degree. C., even
more preferably higher than 40.degree. C.
[0163] Advantageously, when present, said polymer (P) is present in
said composition (C) in an amount higher than 0.1 wt. %, preferably
higher than 0.5 wt. % and more preferably higher than 1 wt. % based
on the total weight of said composition (C).
[0164] Advantageously, said polymer (P) is present in said
composition (C) in an amount lower than 20 wt. %, preferably lower
than 10 wt. % and more preferably lower than 8 wt. % based on the
total weight of said composition (C).
[0165] In a preferred embodiment, said polymer (P) is selected in
the group comprising, preferably consisting of, polyalkylene oxide,
such as notably polyethylene oxide (PEO), polypropylene oxide
(PPO), polybutylene oxide; and poly(vinyl ester), such as poly
(vinyl acetate).
[0166] In a preferred embodiment, composition (C) according to the
present invention comprises: [0167] from 18 to 40.5 w. % of said
medium (L) as defined above, optionally comprising at least one
salt (M) as defined above; [0168] from 2 to 14 w. % of said polymer
(F) as defined above; [0169] from 52 to 82 wt. % of said compound
(EA) as defined above; [0170] from 0.5 to 10 wt. % of said compound
(C); and [0171] optionally, from 3 to 5 wt. % of said polymer
(P).
[0172] The layer (L1) of the electrode (E) of the invention
typically has a thickness comprised between 10 .mu.m and 500 .mu.m,
preferably between 50 .mu.m and 250 .mu.m, more preferably between
70 .mu.m and 150 .mu.m.
[0173] Preferably, under step (i), said substrate is selected from
metal and non-metal substrates. More preferably, said substrate is
selected from the group comprising, even more preferably consisting
of: copper, aluminium, titanium, brass, silver, platinum; graphite;
mixed metal oxide (MMO) electrodes having an oxide coating over an
inert metal or carbon core.
[0174] Preferably, said step (iii) is performed by heating said
composition (C) at a temperature higher than 100.degree. C. until
said polymer (F) is melted.
[0175] Advantageously, step (iii) is performed by heating said
composition (C) at a temperature higher than 100.degree. C. and
preferably lower than 300.degree. C., more preferably lower than
200.degree. C., even more preferably lower than 170.degree. C.
[0176] Advantageously, step (iv) is performed via a hot extruder,
in other words an extruder capable of working at temperature higher
than 100.degree. C.
[0177] Indeed, as composition (C) comprises the medium (L) detailed
above, it is possible to heat the composition (C) such that polymer
(F) is in its melted form, and then extrude the same via hot
extrusion step.
[0178] The Applicant indeed found that compositions that do not
contain the medium (L) in the claimed range cannot be extruded via
the hot extrusion step of the process of the present invention.
[0179] Composition (C) can be advantageously prepared by methods
known to the person skilled in the art.
[0180] Composition (C) is preferably obtained in the form of
paste.
[0181] According to another preferred embodiment, composition (C)
of the invention is composition (C-1), which comprises: [0182] from
10 to 40 wt. % of said medium (L) as defined above, said medium (L)
comprising at least one organic carbonate as the only medium (L);
[0183] from 2 to 14 w. % of said polymer (F**-1) as defined above;
[0184] from 52 to 82 wt. % of said compound (EA) as defined above;
[0185] from 0.5 to 10 wt. % of said compound (C); and [0186]
optionally, from 3 to 5 wt. % of said polymer (P).
[0187] Composition (C-1) according to this preferred embodiment can
be advantageously extruded in the form of pellets, thereby
providing pellets of said composition (C-1) suitable for use in the
preparation of electrodes.
[0188] In a further aspect, the present invention thus relates to
the use of said composition (C-1) in a process for the manufacture
of an assembly, more preferably an electrode [electrode (E)], said
process comprising:
[0189] (a) providing a substrate;
[0190] (b) providing composition (C-1) in the form of pellets, as
defined above;
[0191] (c) heating said composition (C-1) at a temperature higher
than 100.degree. C.;
[0192] (d) extruding the composition (C-1) provided in step (b)
onto the substrate provided in step (a), thereby providing an
assembly comprising a substrate coated with at least one layer
consisting of said composition (C-1).
[0193] In a fourth instance, the present invention pertains to an
electrochemical device comprising the electrode (E) of the
invention.
[0194] In particular, the present invention further pertains to a
secondary battery comprising: [0195] a positive electrode, [0196] a
negative electrode, and [0197] between said positive electrode and
said negative electrode, a membrane,
[0198] wherein at least one of the positive electrode and the
negative electrode is the electrode (E) of the invention.
[0199] The present invention thus also pertains to a process for
the manufacture of a secondary battery, said process comprising
assembling a membrane between a positive electrode and a negative
electrode, wherein at least one of the positive electrode and the
negative electrode is the electrode (E) of the invention.
[0200] Advantageously, in said secondary battery, the positive
electrode is the electrode (E) according to the present
invention.
[0201] Advantageously, in said secondary battery, the negative
electrode is the electrode (E) according to the present
invention.
[0202] It will be apparent to the person skilled in the art that
once the battery is assembled, medium (L) as defined above
comprising salt (M) as defined above, can be further added to the
secondary battery. Said medium (L) and said salt (M) being the same
or different from medium (L) and salt (M) defined for composition
(C) above.
[0203] For the purpose of the present invention, the term
"membrane" is intended to denote a discrete, generally thin,
interface which moderates permeation of chemical species in contact
with it. This interface may be homogeneous, that is, completely
uniform in structure (dense membrane), or it may be chemically or
physically heterogeneous, for example containing voids, pores or
holes of finite dimensions (porous membrane).
[0204] The membrane typically comprises at least one material
selected from inorganic materials and organic materials.
[0205] Non-limiting examples of suitable organic materials include,
notably, polymers, said polymers being preferably selected from the
group consisting of partially fluorinated fluoropolymers.
[0206] The membrane is advantageously free from one or more
compounds (EA) as defined above.
[0207] Depending on the circumstances, the membrane may be a porous
membrane comprising at least one medium (L) as defined above and at
least one salt (M) as defined above. Said embodiment is also
encompassed within the present invention.
[0208] When the membrane comprises said medium (L) and said salt
(M), each of the medium (L) and the salt (M) can be the same or
different from the medium (L) and the salt (M) as used in
composition (C) according to the present invention.
[0209] Should the disclosure of any patents, patent applications,
and publications which are incorporated herein by reference
conflict with the description of the present application to the
extent that it may render a term unclear, the present description
shall take precedence.
[0210] The invention will be now described in more detail with
reference to the following examples whose purpose is merely
illustrative and not limitative of the scope of the invention.
EXPERIMENTAL SECTION
Materials
[0211] Polymer (F.sub.1**): VDF-AA (0.9% by moles)-HFP (2.4% by
moles) polymer having an intrinsic viscosity of 0.28 L/g in DMF at
25.degree. C. and Tm=148.degree. C.
[0212] Polymer (F.sub.2*): VDF-AA (0.9% by moles) polymer having an
intrinsic viscosity of 0.30 L/g in DMF at 25.degree. C. and
Tm=162.degree. C., obtained as described in WO 2008/129041.
[0213] Polymer (F.sub.1**-1): VDF-AA (0.5% by moles)-HFP (6.5% by
moles) polymer having an intrinsic viscosity of 0.32 L/g in DMF at
25.degree. C. and Tm=127.degree. C.
[0214] Polymer (F.sub.3{circumflex over ( )}): VDF-HFP (7% by
moles) polymer having an intrinsic viscosity of 0.08 L/g in DMF at
25.degree. C. and Tm=131.degree. C.
[0215] Silicon/carbon (mixture of silicon and graphite)
commercially available as BTR 480 from BTR with theoretical
capacity was 480 mAh/g.
[0216] Carbon black was commercially available as Super.RTM. C45
and Super.RTM. C65. Graphite was commercially available as Actilion
2. Both from Imerys S.A.
[0217] LFP (lithium iron phosphate) was commercially available as
Life Power.RTM. P2 from Phostech.
[0218] LiTFSI: bis(trifluoromethansulfonyl)imide lithium salt
commercially available from Sigma Aldrich
[0219] Pyr13TFSI: N-propyl-N-methylpyrrolidinium
bis(trifluoromethanesulfonyl)imide commercially available from
Solvionic
[0220] Vinylene carbonate (VC) was commercially available from
Sigma Aldrich.
[0221] Poly ethylene vinyl acetate (EVA) was commercially available
as Greenflex.RTM. MQ 40, with MFI=12 g/10 min and Tm=83.degree.
C.
[0222] Poly(ethylene oxide) (PEO) was commercially available as
Alkox.RTM. E60 with an average molecular weight between
1.times.10.sup.6 and 1.2.times.10.sup.6
[0223] Medium (L1): Pyr13TFSI
[0224] Medium (L2): ethylene carbonate (EC)/propylene carbonate
(PC) 1/1 by volume
Methods
[0225] Determination of intrinsic viscosity of polymers
(F.sub.1**), (F.sub.2*) and (F.sub.3{circumflex over ( )})
[0226] Intrinsic viscosity (.eta.) [dl/g] was measured using the
following equation on the basis of dropping time, at 25.degree. C.,
of a solution obtained by dissolving each of the polymers
(F.sub.1**), (F.sub.2*), (F.sub.1**-1) and (F.sub.3{circumflex over
( )}) in N,N-dimethylformamide at a concentration of about 0.2 g/dl
using a Ubbelhode viscosimeter:
[ .eta. ] = .eta. s .times. p + .GAMMA. ln .times. .times. .eta. r
( 1 + .GAMMA. ) c ##EQU00001##
[0227] where
[0228] c is polymer concentration [g/dl],
[0229] .eta..sub.r is the relative viscosity, i.e. the ratio
between the dropping time of sample solution and the dropping time
of solvent, .eta..sub.sp is the specific viscosity, i.e.
.eta..sub.r-1, and .GAMMA. is an experimental factor, which for
polymers (F.sub.1**), (F.sub.2*), (F.sub.1**-1) and
(F.sub.3{circumflex over ( )}) corresponds to 3.
DSC Analysis
[0230] DSC analyses were carried out according to ASTM D 3418
standard; the melting point (Tm) was determined at a heating rate
of 10.degree. C./min.
Preparation of the Electrodes
[0231] The ingredients in the amounts reported in the Tables below
were mixed together so as to obtain for each mixture a paste.
[0232] Each paste thus obtained was introduced into the feeding
hopper of a mini-extruder and melt blended using a co-rotating twin
screw micro extruder DSM Xplore 15 ml Microcompounder. The micro
extruder was formed by a divisible fluid tight mixing compartment
containing two detachable, conical mixing screws. Residence time
was recorded. The screw speed was fixed at 50 rpm for the mixing
and sometimes higher during the exit of the extrudate. The heating
temperature was set at 200.degree. C. or 230.degree. C. At the end
of the mixing time the material was extruded through the nozzle.
Immediately out of the nozzle, the extruded profile was laid on a
copper film keep warm by a steel plate placed under it and
preheated at 230.degree. C. Using a little roller covered by a
detaching adhesive, the extruded was manually pressed. The result
was a strip which remains attached to the copper or aluminium film
with a total thickness of about 500 um.
[0233] This sheet composed of several strips was placed in a
compression molding machine heating at the temperatures detailed
below, between two foils of PTFE. A pressure as detailed below was
applied, thus obtaining an electrode (anode or cathode) having the
thickness reported below.
Example A--Compositions for Preparing the Anodes
[0234] Each of the compositions of Example 1 and Example 2 was
extruded at a temperature of 200.degree. C. Residence time in the
extruder was 5 minutes. RPM=50.
[0235] As the composition came out of the extruder, it was placed
onto a copper metal collector and then pressed at 230.degree. C.
and 200 bars, thus obtaining a SiC electrode.
TABLE-US-00001 TABLE 1 Example Example 1 Example 2 1C(*) amounts
amounts Amounts Wt. Wt. Wt. Ingredient g % g % g % Medium L-1 6
23.1 5.1 22.2 2.2 9 with 0.5M of LiTFSI Binder F.sub.1** 2 7.7 1.7
7.4 2.3 9.3 Active BM480 17.8 68.5 15.1 65.9 20.1 80.9 material BTR
Conductive SC45 0.2 0.7 0.2 0.7 0.2 0.8 carbon Polymer P PEO -- --
0.9 3.8 -- -- Thickness of the 230 .mu.m 200 .mu.m n/p electrode
(*) comparison n/p = not performed
[0236] The adhesion was measured and the results are provided in
Table 5.
[0237] The composition of Example 1C(*) of comparison contained an
amount of medium (L-1) outside the claimed scope. This composition
could not be extruded.
Example A1--Compositions for Preparing the Anodes
[0238] Each of the compositions of Example 1A and Example 2A was
extruded at a temperature of 130.degree. C. Residence time in the
extruder was 5 minutes. RPM=50.
[0239] As the composition came out of the extruder, it was placed
onto a copper metal collector and then pressed at 130.degree. C.
and 200 bars, thus obtaining a graphite electrode.
TABLE-US-00002 TABLE 1A Example 1A Example 2A amounts amounts
Ingredient g Wt. % g Wt. % Medium L-2 with 10% 3.42 18 5.36 25.5 wt
of LiTFSI Binder F.sub.1**-1 1.9 10 1.91 9.1 Active material
graphite 13.49 71 13.55 64.5 Conductive carbon SC65 0.19 1 0.19 0.9
Thickness of the electrode 95 .mu.m 55 .mu.m
[0240] The adhesion was measured and the results are provided in
Table 5.
Example B--Composition for Preparing an LFP Cathode
[0241] The composition of Example 3 was extruded at a temperature
of 230.degree. C. Residence time in the extruder was 4 minutes.
RPM=50. As the composition came out of the extruder, it was placed
onto an aluminium metal collector and then pressed at 230.degree.
C. and 200 bars, thus obtaining a LFP electrode.
TABLE-US-00003 TABLE 2 Example 3 amounts Ingredient g Wt. % Medium
L-1 with 0.5 M 4.7 23.27 of LiTFSI Binder F.sub.1** 2.0 9.97 Active
material LFP Phostec 11.3 56.79 Conductive carbon SC45 2.0 9.97
Thickness of the electrode 160 .mu.m
[0242] The adhesion was measured and the results are provided in
Table 5.
Example C--Compositions for Preparing the Anodes
[0243] Each of the compositions of Example 4, Example 5 and Example
6 was extruded at a temperature of 200.degree. C. Residence time in
the extruder was 5 minutes. RPM=50. As the compositions came out of
the extruder, they were placed onto a copper metal collector and
then pressed at 230.degree. C. and 200 bars, thus obtaining a
graphite electrode.
TABLE-US-00004 TABLE 3 Example 4 Example 5 Example 6 amounts
amounts amounts Wt. Wt. Wt. Ingredient g % g % g % Medium L-1 10.41
40.1 3.6 18 3.6 18 with 0.5M of LiTFI Binder F.sub.1** 2.31 8.9 --
-- -- -- F.sub.2* -- -- 2.4 12 1.8 9 Active Actilion 13.13 50.4
13.8 69 13.8 69 material 2 Conductive SC65 0.144 0.6 0.2 1 0.2 1
carbon Polymer P EVA -- -- -- -- 0.6 3 Thickness of the 120 .mu.m
220 .mu.m 120 .mu.m electrode
[0244] The adhesion was measured and the results are provided in
Table 5.
Example D--Compositions for Preparing the Anodes
[0245] The composition of Example 7 was extruded at a temperature
of 140.degree. C. Residence time in the extruder was 5 minutes.
RPM=50. As the composition came out of the extruder, it was placed
onto a copper metal collector and then pressed at 140.degree. C.
and 200 bars, thus obtaining a graphite electrode.
TABLE-US-00005 TABLE 4 Example 7 Example 2C (*) amounts amounts
Ingredient g Wt. % G Wt. % Medium L-2 with 3.6 18 0 0 1 M of LiTFI
Binder F.sub.3{circumflex over ( )} 2.4 12 2.4 14.1 Active material
graphite 13.8 69 13.8 81.2 Conductive carbon SC65 0.2 1 0.2 1.2
Polymer P EVA -- -- 0.6 3.5 Thickness of the electrode 200 .mu.m
n/p (*) comparison n/p = not performed
[0246] The composition of Example 2C(*) of comparison contained an
amount of medium (L) outside the claimed scope. This composition
could not be extruded.
Adhesion Test
[0247] The peeling tests were performed in order to evaluate the
adhesion of the electrode composition coating onto the metal
support. The test was performed on the electrodes prepared as
described above, following the procedure of ASTM D903, working at a
speed of 300 mm/min at 20.degree. C.
[0248] A value higher than 10 N/m was considered acceptable and
good performing for use in battery application.
TABLE-US-00006 TABLE 5 Example Substrate Adhesion (N/m) 1 Copper
100 2 Copper 98 1A Copper 90 2A Copper 106 3 Aluminium 49 4 Copper
28 5 Copper 45 6 Copper 88
[0249] All the electrodes prepared in accordance with the present
invention showed adhesion values to current collector higher than
the minimum required for battery applications.
Example E--Preparation of aBbattery
[0250] Two lithium coin cells (CR2032 type, diameter of 20 mm) were
prepared in a glove box under an Ar gas atmosphere, by punching a
small disk (diameter=12 mm) of the electrode prepared using the
composition of Example 3, with lithium metal as a reference
electrode.
[0251] The electrolyte used in the preparation of the coin cells
was a standard 1M LiPF6 solution in EC/DMC in ratio 1/1, with 2 wt.
% of VC additive.
[0252] Polyethylene separators (commercially available from Tonen
Chemical Corporation) were used as received.
Capacity Retention Test
[0253] After initial charge and discharge cycles at a low current
rate (formation phase), each of the two cells prepared as described
in Example E were galvanostatically cycled at a constant current
rate of C/5-D/5 with positive cut off of 4V and negative cut off of
2.5V.
[0254] The data obtained are reported in Table 6 below.
TABLE-US-00007 TABLE 6 Retention after 25 cycles (% Coulombic with
respect to Loading efficiency at Initial capacity first cycle at
(mAh/cm.sup.2) cycle 1 (%) (mAh/g) C/5) 4.05 98.2 155 98.8 3.74
98.0 142 99.4
[0255] Both cells showed very good coulombic efficiency, initial
capacity and retention after 25 cycles.
* * * * *